A microstate or ministate is a sovereign state having a very small population or very small land area, but usually both. As the meaning of neither "state" nor "very small" is clear,[1] the recent attempts to define microstates focus on identifying political entities with unique qualitative features linked to their geographic or demographic limitations. According to a qualitative definition, microstates are: "modern protected states, i.e. sovereign states that have been able to unilaterally depute certain attributes of sovereignty to larger powers in exchange for benign protection of their political and economic viability against their geographic or demographic constraints."[2] In line with this and most other definitions the examples of microstates include: Liechtenstein, Monaco, San Marino, Niue and the Federated States of Micronesia.

The smallest political unit recognized as a sovereign state is Vatican City, with 842 citizens as of July 2013 and an area of only 0.44 km². However, some scholars dispute qualifying Vatican as a state arguing that it does not meet the "traditional criteria of statehood" and that the "special status of the Vatican City is probably best regarded as a means of ensuring that the Pope can freely exercise his spiritual functions, and in this respect is loosely analogous to that of the headquarters of international organisations."[3]

Most scholars identify microstates by using a quantitative threshold and applying it to either one variable (such as territory[4] or population[5] size) or a composite of different variables.[6] While it is agreed that microstates are the smallest of all states, there is no consensus on what variable (or variables) or what cut-off point should be used to determine which political units should be labelled as "microstates" (as opposed to small states or "normal" states).[1][2][7][8]

With the exceptions of Samoa, Vanuatu, Iceland, Bahamas, Belize, and Brunei, all the above have a non-sea area less than 1,000 km2 (386 sq mi).

While employing simple quantitative criteria may seem straightforward, it can also be perceived as potentially problematic. According to some scholars the quantitative approach to defining microstates suffers from such problems as "inconsistency, arbitrariness, vagueness and inability to meaningfully isolate qualitatively distinct political units"[2]

In response to the problems associated with the quantitative definitions of microstates, some academics have suggested finding states with unique features linked to their geographic or demographic smallness.[2][12][13] Newer approaches have proposed looking at the behaviour or capacity to operate in the international arena in order to determine which states should deserve the microstate label.[13][14] Yet, it has argued been that such approaches could lead to either confusing microstates with weak states[7][12] (or failed states) or relying too much on subjective perceptions.[2]

In order to address both the problems with quantitative approaches and with definitions based on qualitative features, it has been argued that a useful and meaningful to isolate microstates from other types of states, would be to see them as "modern protected states".[2] According to the definition proposed by Dumienski (2014): "microstates are modern protected states, i.e. sovereign states that have been able to unilaterally depute certain attributes of sovereignty to larger powers in exchange for benign protection of their political and economic viability against their geographic or demographic constraints."[2] Adopting this approach permits limiting the number of microstates and separating them from both small states and autonomies or dependencies.[2] Examples of microstates understood as modern protected states include such states as: Liechtenstein, San Marino, Monaco, Niue, the Cook Islands or Palau.

A small number of tiny sovereign political units are founded on historical anomalies or eccentric interpretations of law. These types of states, often labelled as "microstates," are usually located on small (usually disputed) territorial enclaves, generate limited economic activity founded on tourism and philatelic and numismatic sales, and are tolerated or ignored by the nations from which they claim to have seceded.

Another example is the Cospaia Republic, which became independent through a treaty error and survived from 1440 to 1826. Its independence made it important in the introduction of tobacco cultivation to Italy.